1. Field of the Invention
Embodiments of the present invention are generally directed to a system and method for removing a coating from a substrate.
2. Description of the Related Art
Systems and methods for removing a coating from a substrate, such as a wall, building, fence, etc., are well-known. A common system for removing a coating is a dry sandblaster. The typical sandblaster operates by projecting a pressurized stream of air of 150 psi and sand, such as silica, against the substrate so as to chisel the coating off the substrate. Generally, dry sandblasters are only used on hard substrates, such as steel and concrete. When used on less durable substrates the sandblaster often does more harm than good. If care is not taken to properly use the sandblaster, including an appropriate pressure amount for the substrate, the sandblaster will remove not only the coating but also portions of the substrate. Conversely, if too little pressure is used, the sandblaster fails to remove the coating. Moreover, use of a sandblaster often leaves unwanted sand residue around the area being cleaned due to the large quantities of cleaning medium consumed. A typical dry sand blaster consumes around 440 pounds of cleaning medium per hour. Dry sandblasters also generate harmful dust, requiring breathing protection be worn by the operator at all times when in use. Damage to the substrate by dry sandblasting can be reduced by varying the type of cleaning medium to a more gentle alternative than sand, but dust generation is still a primary hazard.
An alternative to harmful dry sandblasters is a wet sandblaster. A wet sandblaster employs water as the carrier to move the cleaning media from the cleaning medium source into the pressurized air stream. The water eliminates the dust hazards associated with dry sandblasting and can also reduce damage to the substrate. An average wet sandblaster using a 185 cfm air compressor consumes about 300 pounds of cleaning medium and 60 gallons of water per hour, producing a cleaning medium to water ratio of approximately 1:3. The defects in wet sandblasters are that spent wet cleaning medium is difficult and time consuming to remove from the job site. Additionally, the large volumes of water required demand that a source of water be present at the job site, provided by either a tap or a tanker.
Another system for removing a coating from a substrate is a high-pressure washer that deploys water or other cleaning fluid under high pressures of from 1500 psi to over 50,000 psi. Although the pressure washer does not employ sand, and therefore, limits the amount of damage that can be done to the substrate, the pressure washer still must be used carefully and only on substrates that again can withstand the pressures generated. Moreover, like the wet sandblaster, the pressure washer employs a large amount of water to accomplish the coating removal. Water consumption ranges from 120 to 600 gallons per hour, depending on the requirements of the washer. As with wet sandblasting, the large volumes of water consumed demand that a source of water be present at the job site. The high pressures also broadcast removed debris and waste water over surrounding areas. Therefore, use of the pressure washer in interior spaces is not preferred, as the waste water can possibly harm surrounding surfaces and be a nuisance to clean up.
Accordingly, there is a need for a system and a method for removing a coating from a substrate that does not rely on a large amount of water and/or a large amount of cleaning medium to accomplish the removal of the coating. Additionally, there is a need for a system and a method that can be used in locations where waste water outputted during operation is undesired. Moreover, there is a need for a system and a method operating at low pressures that can efficiently remove coatings with little or no damage to the substrate.